1. Field
The present disclosure relates to a hybrid electronic sheet and a method for preparing the same.
2. Description of the Related Art
Researches on flexible high-performance materials and devices such as wearable computers, bendable displays, wearable biomedical electrodes and biosensors for health monitoring, human-robot interfaces, etc. are rapidly increasing nowadays. For such applications, development of a material which has excellent electrical property as well as superior mechanical property and to which biochemical or biological property can be further provided in addition to the electrical property, e.g., as in wearable biosensors, is of great importance. In addition, for realization of a high-performance device composed of various constituents on a flexible substrate, low contact resistance is required between the constituents and superior contact property with the flexible substrate is necessary.
Since carbon nanomaterials such as carbon nanotube, graphene, etc. have excellent electrical, mechanical and chemical properties, use of the materials as an electrode of flexible electronic devices, flexible bioelectrodes, sensors, flexible energy devices, etc. is actively studied recently.
For application of graphene or carbon nanotube to flexible devices, a process of transferring the graphene or carbon nanotube synthesized at high temperature without decrease in electrical property is essential. In addition, for effective operation of a high-performance device, effective electrical contact property between the carbon nanomaterial and other constituents of the device and resistance property on the flexible substrate are very important. Carbon nanotube is commonly used by depositing a film on a substrate, for example, by spin coating the carbon nanotube dispersed in an organic solvent or by forming a film through vacuum filtration and dissolving out the filter membrane chemically to obtain a carbon nanotube film. However, these methods are problematic in that the performance of the device is decreased or contact property with a flexible substrate is unsatisfactory due to an organic solvent or a dispersant remaining after chemical etching. Also, transfer onto a substrate with a complex shape is impossible because of large film thickness and patterning which is essential for realization of the device is difficult.
Graphene is used by growing the graphene on the surface of a metal such as copper by chemical vapor deposition (CVD) and transferring onto a desired substrate using an etching solution or by reducing chemically prepared graphene oxide through spin coating to obtain a reduced graphene oxide film. However, the CVD-grown graphene is disadvantageous in that use of an environmentally very harmful etching solution is necessary and effective surface area per unit area is very small because the graphene consists of a single or only a few layer(s). Further, because graphene is chemically stable, it is not easy to confer additional properties to the graphene. The reduced graphene oxide is disadvantageous in that electrical property is not excellent because a process of chemically reducing the graphene oxide which has been chemically oxidized is required.
When preparing a flexible electrode including a biomaterial such as a biosensor electrode, it is important to realize a high-performance flexible device without chemical etching. However, with the existing methods, it is difficult to realize a flexible device having superior electrical property wherein a biomaterial is nanohybridized.